X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/3d25ce2fc68666d4b674c4f710cde362aa584632..d53d00d608a60a6f05e77ea7b7cd5c4e544d7ab1:/src/smpi/colls/reduce-flat-tree.cpp

diff --git a/src/smpi/colls/reduce-flat-tree.cpp b/src/smpi/colls/reduce-flat-tree.cpp
new file mode 100644
index 0000000000..685fc2ff04
--- /dev/null
+++ b/src/smpi/colls/reduce-flat-tree.cpp
@@ -0,0 +1,68 @@
+/* Copyright (c) 2013-2014. The SimGrid Team.
+ * All rights reserved.                                                     */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "colls_private.h"
+//#include <star-reduction.c>
+
+int
+smpi_coll_tuned_reduce_flat_tree(void *sbuf, void *rbuf, int count,
+                                 MPI_Datatype dtype, MPI_Op op,
+                                 int root, MPI_Comm comm)
+{
+  int i, tag = COLL_TAG_REDUCE;
+  int size;
+  int rank;
+  MPI_Aint extent;
+  char *origin = 0;
+  char *inbuf;
+  MPI_Status status;
+
+  rank = smpi_comm_rank(comm);
+  size = smpi_comm_size(comm);
+
+  /* If not root, send data to the root. */
+  extent = smpi_datatype_get_extent(dtype);
+
+  if (rank != root) {
+    smpi_mpi_send(sbuf, count, dtype, root, tag, comm);
+    return 0;
+  }
+
+  /* Root receives and reduces messages.  Allocate buffer to receive
+     messages. */
+
+  if (size > 1)
+    origin = (char *) smpi_get_tmp_recvbuffer(count * extent);
+
+
+  /* Initialize the receive buffer. */
+  if (rank == (size - 1))
+    smpi_mpi_sendrecv(sbuf, count, dtype, rank, tag,
+                 rbuf, count, dtype, rank, tag, comm, &status);
+  else
+    smpi_mpi_recv(rbuf, count, dtype, size - 1, tag, comm, &status);
+
+  /* Loop receiving and calling reduction function (C or Fortran). */
+
+  for (i = size - 2; i >= 0; --i) {
+    if (rank == i)
+      inbuf = static_cast<char*>(sbuf);
+    else {
+      smpi_mpi_recv(origin, count, dtype, i, tag, comm, &status);
+      inbuf = origin;
+    }
+
+    /* Call reduction function. */
+    smpi_op_apply(op, inbuf, rbuf, &count, &dtype);
+
+  }
+
+  if (origin)
+    smpi_free_tmp_buffer(origin);
+
+  /* All done */
+  return 0;
+}